Device and Methods for Attaching Sacrificial Anodes

ABSTRACT

A sacrificial anode contains a powerful magnet which pulls it against an object comprising ferromagnetic metal and thus fastens the anode to the ferromagnetic metal. The magnet itself is encased in an electrically inert substance and thus does not corrode.

PRIORITY

This disclosure claims the priority of U.S. Ser. No. 62/240,535 filed on Oct. 13, 2015, the contents of which are wholly included herein.

FIELD OF INVENTION

This pertains to the field of protection of iron, nickel and steel from corrosion.

BACKGROUND

Corrosion in iron, steel, nickel and other ferromagnetic metals is accelerated by the presence of an electrolytic solution. Heat accelerates the reaction causing this corrosion but is not essential to it. The reaction happens because the ferromagnetic metal and water form part of a circuit where part of the ferromagnetic metal becomes the anode, and part of the ferromagnetic metal becomes the cathode. The ferromagnetic metal in the anode gives up its electrons, which migrate to the cathode. Simultaneously at the anode ions of the ferromagnetic metal break free into the electrolyte and combine with the H2O—to form rust.

A common way to prevent corrosion in an object made of ferromagnetic metal is to use sacrificial anodes. A sacrificial anode consists of a different metal from the ferromagnetic object. The sacrificial anode is in contact with the ferromagnetic object to form an electrical circuit. The metal of the sacrificial anode has greater electronegativity than the ferromagnetic metal, i.e. the sacrificial anode metal gives up its electrons more readily than the ferromagnetic metal. Thus the current in the electrical circuit passes from the sacrificial anode into the electrolytic solution, rather than from the ferromagnetic metal into the electrolytic solution. This causes the sacrificial anode rather than the ferromagnetic object to corrode. Eventually the sacrificial anode is consumed by corrosion and must be replaced.

Examples of the use of sacrificial anodes include but are not limited to:

-   -   sacrificial anodes placed on steel pipe laid underground     -   zinc anodic weights welded to the outside of ships & boats     -   galvanization of nails

This is all well known and well understood in the Art.

PRIOR ART

U.S. Pat. No. 7,402,233 (Glen Morgan) teaches an apparatus where a sacrificial anode contains a magnet and attaches to a metallic substrate by an electrically conductive adhesive. In this case the magnet is not intended to hold the sacrificial anode fast to the metallic substrate.

SUMMARY OF THE APPARATUS

The present disclosure teaches a device which comprises a powerful magnet and a sacrificial anode. The sacrificial anode comprises metal with greater electronegativity than the ferromagnetic object. The magnet is electrically segregated and therefore prevented from being part of any circuit. The magnet pulls the sacrificial anode against an object comprising ferromagnetic metal, called a ferromagnetic object, and thereby maintains a strong physical contact between the ferromagnetic object and the sacrificial anode.

When both the sacrificial anode and the ferromagnetic object are in contact with a continuous volume of electrolytic solution, then an electrical circuit forms which comprises the electrolytic solution, the ferromagnetic object and the sacrificial anode. Electric current flows through this electrical circuit, from the ferromagnetic object through the sacrificial anode and into the electrolytic solution. This current flow corrodes the sacrificial anode. However current does not flow directly from the ferromagnetic object into the electrolytic solution, and therefore the ferromagnetic object does not corrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment. Here an object made of ferromagnetic metal (101) abuts a tablet of zinc (102), electrolytic water (103) and another tablet of a tin/bismuth allow (104). A magnet (105) and the other devices are embedded in a matrix of rubber (106) which holds items 102, 104 and 105 together. The magnet (105) pulls the device comprising 102, 104, 105 and 106 to the ferromagnetic object (101) and fastens the device to the ferromagnetic object.

EMBODIMENTS Anode Piece

In an embodiment the anode piece comprises a metal which is more electronegative than the ferromagnetic metal. The anode piece has one surface adapted to be placed in strong physical contact with some ferromagnetic object.

All embodiments have at least one anode piece present.

In some embodiments the anode piece is in the shape of a tablet. In some embodiments the anode piece is in some other shape.

In some embodiments the anode piece comprises zinc. In some embodiments it comprises some other metal.

Cathode Piece

In some embodiments cathode piece comprises a metal which is less electronegative than the ferromagnetic object. The cathode piece has one surface adapted to be placed in strong physical contact with some ferromagnetic object.

The intent is that if a cathode piece is present then in the presence of electrolytic solution an electric circuit forms connecting in a loop:

-   -   the ferromagnetic object     -   the anode piece     -   the electrolytic solution     -   the cathode piece

The cathode piece does not corrode. Instead it receives free electrons which migrate from the anode piece through the ferromagnetic object, and through the cathode piece. When these electrons reach the electrolytic solution they combine with positive ions in the solution.

In some embodiments where a cathode piece is present the cathode piece is in the shape of a tablet. In some embodiments the cathode piece is in some other shape.

In some embodiments where a cathode piece is present the cathode piece comprises bismuth. In some embodiments it comprises tin. In some embodiments it comprises some other metal.

Core Device

In an embodiment of the invention a core device comprises a matrix of some material which binds with a plurality of pieces of metal and a plurality of magnets in such a way that the pieces of metal and the magnets do not come loose from the matrix.

The core device is adapted to bind to a ferromagnetic object due to the inherent attraction of the magnets, in such a way that in this configuration the metal pieces maintain a strong physical contract with the ferromagnetic object, while simultaneously either allowing or providing an electrolytic solution to maintain physical contact with both the metal pieces and the ferromagnetic object.

Matrix

In some embodiments the matrix comprises rubber. In some embodiments the matrix comprises some other elastomer. In some embodiments the matrix comprises plastic. In some embodiments the matrix comprises epoxy. In some embodiments the matrix comprises glass. In some embodiments the matrix comprises some other material.

Magnet

In an embodiment magnet is strong enough to pull the device to an object made of ferromagnetic metal and hold it with sufficient force to maintain a strong physical contract between the anode piece and the ferromagnetic object.

In some embodiments the magnet is electrically isolated because the matrix is electrically inert and completely insulates the magnet electrically.

In some embodiments the magnet comprises iron. In some embodiments the magnet comprises neodynium. In some embodiments the magnet contains some other metal.

Core Anode Device

In some embodiments a core anode device is a core device with metal pieces which are anode pieces.

In some embodiments the core anode device is solid. In some embodiments the core anode device is porous. In some embodiments the core anode device is hollow. In some embodiments the core anode device is of some other material form.

Core Cathode Device

In some embodiments a core cathode device is a core device where the metal pieces are cathode pieces.

In some embodiments at least one core anode device and at least one core cathode device both attach to a ferromagnetic object.

In some embodiments the core device is solid. In some embodiments the core device is porous. In some embodiments the core device is hollow. In some embodiments the core device is of some other material form.

Core Combined Device

In some embodiments a core combined device is a core device where at least one metal piece is an anode piece, and at least one metal piece is a cathode piece.

In some embodiments a core combined device has at least one anode piece and at least one cathode piece touch a ferromagnetic object.

In some embodiments when the anode piece and cathode piece touch a ferromagnetic object, then between the pieces there is a gap where fluid may reside.

Reservoir

In some embodiments there exists a reservoir holding an electrolytic solution. In such embodiments the fluid in the reservoir touches both the anode piece and the ferromagnetic object. In an embodiment where both a reservoir and a cathode piece are present the fluid in the reservoir touches the cathode piece as well.

The intent of the reservoir is to ensure the existence of a circuit comprising the ferromagnetic object, the anode piece and the electrolytic solution; and also the cathode piece, if one is present.

In some embodiments the reservoir holds water containing NaCl. In some embodiments the reservoir contains some other electrolytic solution.

Open Access to Electrolytic Solutions

In some embodiments an electric circuit forms if and only if some unbroken volume of electrolytic solution present in the environment touches the anode piece and either the ferromagnetic object, or a cathode piece, or both.

The intent is in such embodiments the circuit forms and corrosion occurs only when an electrolytic solution is environmentally present. An example of this is if an automobile has the device attached at the undercarriage, and water mixed with road salt splashes up and wets both the ferromagnetic object—in this case the car's undercarriage and also the anode object which is part of the device In this event a circuit forms. But once the water evaporates the circuit again ceases to exist.

Note that corrosion can occur even when an electrolytic solution is absent, but the rate is much slower. The intent is to retard corrosion when the electrolytic solution is abundant.

Handle

In some embodiments the matrix has attached to it a handle adapted to being handled manually.

Core Function

In an embodiment the device touches a ferromagnetic object by its piece. The force of the magnet pulls it to the object and holds it fast.

In an embodiment when there is electrolytic fluid around the pieces and the ferromagnetic object sufficient to form a circuit then current flow passes through the sacrificial anode and corrodes it, rather than corroding the ferromagnetic object, thereby decreasing corrosion on the ferromagnetic object.

In some embodiments where a cathode piece is present the cathode piece forms the cathode to complete the circuit in the presence of an electrolytic solution. In some embodiments where no cathode piece is present the ferromagnetic object itself becomes the cathode to complete the circuit in the presence of an electrolytic solution.

Attaching the Device

In an embodiment to attach the device one places it on a ferromagnetic object. The magnet holds it fast to the object.

In some embodiments where a handle is present one manually holds the handle to perform this action.

Detaching the Device

In an embodiment to detach the device one pulls it from the ferromagnetic object with sufficient force to overcome the magnetic attraction of the device to the object.

In some embodiments where a handle is present one manually holds the handle to perform this action.

Example Embodiment

In an example embodiment as shown in FIG. 1 the device comprises a matrix (106) which has been placed on an ferromagnetic object (101). The magnetic force of the magnet (105) pulls the device to the object (101) and holds it fast. The zinc sacrificial anode piece (102) and the bismuth/tin alloy cathode piece (104) touch the object (101). Electrolytic solution (103) sits between and around them. The object (101), anode (102), solution (103) and cathode (104) comprise a circuit. The anode (102) corrodes but the object (101) does not.

Example Embodiment Showing Use

In an example embodiment the device attaches to the ferromagnetic hull of a ship. It is held in place by magnetic force from the magnet. The sacrificial anode touches the hull of the ship, completing a circuit between the sacrificial anode, the hull and the elecrolytic seawater when the device is under the surface of the sea.

Example Embodiment Showing Use

In an example embodiment the device comprises a metallic wool sacrificial anode, for instance galvanized steel wool. The device is adapted to hold a razor or razor blade comprising ferromagnetic metal, for such times that the razor or razor blade is unused. At such times, if electrolytic moisture is present on the razor blade then the device, the razor blade and the moisture form a circuit, and this prevents the razor blade from corroding.

Other Embodiments

We show these varied and numerous embodiments of the invention to be exemplary and in no way limiting. Many other embodiments are possible, without departing from the spirit of the invention or sacrificing its advantages.

Advantages and Conclusions

The device is inexpensive to manufacture, since its component parts—a magnet, metal pieces, and a matrix to tie it all together—are all cheap.

The device attaches with no trouble to any plate of ferromagnetic metal. There is no need of tooling or manufacturing the ferromagnetic object one is trying to protect from rust. 

I claim:
 1. A device comprising: a) at least one electrode of a type drawn from the following set: <i> a sacrificial anode comprising some metal with greater electronegativity than ferromagnetic metals; <ii> a cathode comprising some metal with lower electronegativity than ferromagnetic metals; and; b) a magnet which is: <i> adapted to attract to an object comprising iron or steel with sufficient force to hold said device fast in such a manner that said sacrificial anode touches said object; and <ii> encased in an electrically inert material which disallows said magnet from forming an electrical circuit; where: c) said device has geometry such that when device is attached to said object, permits fluid surrounding it to touch both said sacrificial anodes and said object; and d) where said device does not comprise any adhesive to attach it to another object; the improvement over prior art being the absence of an electrically conductive adhesive in said device.
 2. The device of claim 1 also comprising a handle adapted to being grasped manually.
 3. A method of the device of claim 1 where a person attaches said device to an object comprising ferromagnetic metal by simply placing said device against said object and allowing the magnetic force of said device to fasten said device to said object.
 4. A method of the device of claim 1 where when said device fastens to an object comprising ferromagnetic metal, a person detaches said device by pulling said device off of said object.
 5. A method of the device of claim 1 where said electrode is a sacrificial anode and when said device is fastened to an object of ferromagnetic metal in an environment containing sufficient electrolytic fluid that a circuit forms comprising said object of ferromagnetic metal, said sacrificial anode and said electrolytic fluid; thereby corroding said sacrificial anode rather than said object of ferromagnetic metal.
 6. The device of claim 1 where: a) at least one electrode is a sacrificial anode; and b) at least one electrode is a cathode; where: c) when said device attaches to said object then both said anode and said cathode touches said object; and c) said device has geometry such that when device is attached to said object, permits fluid surrounding it to touch both said sacrificial anode and said cathode.
 7. A method of the device of claim 6 where when said device is attached to an object of ferromagnetic metal in an environment containing sufficient electrolytic fluid that a circuit forms comprising said cathode, said object of ferromagnetic metal, said anode and said electrolytic fluid; thereby corroding said anode rather than said object of ferromagnetic metal.
 8. The device of claim 1 also comprising a reservoir of electrolytic fluid such that when said device fastens to a ferromagnetic object said reservoir is in contact with both said electrode and said object, thereby forming an electrical circuit. 